This invention relates to a control valve for use in automatically controlling the vacuum as in a deicer pad.
Deicer pads are inflatable or resilient extensible units mounted as shoes or pads upon the leading edges of an airplane airfoil and are used for the purpose of preventing the accumulation of ice on the airfoils.
In the control of such deicer pads, many systems have employed extensive complicated air conduits supplied with pressurized air and thence having a vacuum pulled therethrough wherein the operation is repeated numerous times. The pulling of a vacuum is achieved by a vacuum pump operating in conjunction with a motor-driven distributor valve which supplies air under pressure to the deicer pad. The present invention is directed to a novel valve which automatically adjusts to produce a preset level of vacuum which has the advantage of operating with a minimum of compressed air, regardless of the pressure, thus drawing less power when less flow is needed to maintain a vacuum.